An efficient and stable hybrid extended Lagrangian/self-consistent field scheme for solving classical mutual induction

Journal Article · Sat Nov 07 00:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4933375· OSTI ID:22493189

Albaugh, Alex ^[1]; Demerdash, Omar ^[2]; Head-Gordon, Teresa ^[1]

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1. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720 (United States)
2. Department of Chemistry, University of California, Berkeley, California 94720 (United States)

We have adapted a hybrid extended Lagrangian self-consistent field (EL/SCF) approach, developed for time reversible Born Oppenheimer molecular dynamics for quantum electronic degrees of freedom, to the problem of classical polarization. In this context, the initial guess for the mutual induction calculation is treated by auxiliary induced dipole variables evolved via a time-reversible velocity Verlet scheme. However, we find numerical instability, which is manifested as an accumulation in the auxiliary velocity variables, that in turn results in an unacceptable increase in the number of SCF cycles to meet even loose convergence tolerances for the real induced dipoles over the course of a 1 ns trajectory of the AMOEBA14 water model. By diagnosing the numerical instability as a problem of resonances that corrupt the dynamics, we introduce a simple thermostating scheme, illustrated using Berendsen weak coupling and Nose-Hoover chain thermostats, applied to the auxiliary dipole velocities. We find that the inertial EL/SCF (iEL/SCF) method provides superior energy conservation with less stringent convergence thresholds and a correspondingly small number of SCF cycles, to reproduce all properties of the polarization model in the NVT and NVE ensembles accurately. Our iEL/SCF approach is a clear improvement over standard SCF approaches to classical mutual induction calculations and would be worth investigating for application to ab initio molecular dynamics as well.

• OSTI ID: 22493189
• Journal Information: Journal of Chemical Physics, Vol. 143, Issue 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
97 MATHEMATICAL METHODS AND COMPUTING
BORN-OPPENHEIMER APPROXIMATION
CONVERGENCE
DEGREES OF FREEDOM
DIPOLES
ENERGY CONSERVATION
LAGRANGIAN FUNCTION
MOLECULAR DYNAMICS METHOD
POLARIZATION
QUANTUM ELECTRONICS
SELF-CONSISTENT FIELD
THERMOSTATS
WATER